Allow more fine grained control over QFont debug output

With verbosity level 0, only the resolved properties are included
in the debug output, which is useful when debugging font resolving.

With verbosity level 1, the family, size, and weights are included,
plus any resolved property that is different from the default value.

Verbosity level 2, the QDebug default, has been kept unchanged,
except removing quotes and spaces by adding nospace() and qPrintable.

Verbosity level 3 includes all properties, regardless of whether or
not they have been resolved.

Levels 1 and 3 also include the resolve mask, to aid debugging.

This gives the following results for a QFont set to 100pt:

  QFont(100pt)
  QFont(".SF NS Text", 100pt, Weight::Normal, resolveMask=SizeResolved)
  QFont(.SF NS Text,100,-1,5,50,0,0,0,0,0)
  QFont(".SF NS Text", 100pt, StyleHint::AnyStyle, StyleStrategy::PreferDefault,
    Weight::Normal, StyleNormal, underline=false, overline=false, strikeOut=false,
    fixedPitch=false, AnyStretch, kerning=true, MixedCase, letterSpacing=0
    (PercentageSpacing), PreferDefaultHinting, styleName="", resolveMask=SizeResolved)

Change-Id: Ib4aebd7346ef4a2946cc4450c12730cf7844c3bc
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

2 files changed, 104 insertions, 1 deletions

diff --git a/src/gui/text/qfont.cpp b/src/gui/text/qfont.cpp
index d879836572..82e03b6df9 100644
--- a/src/gui/text/qfont.cpp
+++ b/src/gui/text/qfont.cpp
@@ -3161,7 +3161,104 @@ void QFontCache::decreaseCache()
 #ifndef QT_NO_DEBUG_STREAM
 QDebug operator<<(QDebug stream, const QFont &font)
 {
-    return stream << "QFont(" << font.toString() << ')';
+    QDebugStateSaver saver(stream);
+    stream.nospace().noquote();
+    stream << "QFont(";
+
+    if (stream.verbosity() == QDebug::DefaultVerbosity) {
+        stream << font.toString() << ")";
+        return stream;
+    }
+
+    QString fontDescription;
+    QDebug debug(&fontDescription);
+    debug.nospace();
+
+    QFontPrivate priv;
+    const QFont defaultFont(&priv);
+
+    for (int property = QFont::FamilyResolved; property < QFont::AllPropertiesResolved; property <<= 1) {
+        const bool resolved = (font.resolve_mask & property) != 0;
+        if (!resolved && stream.verbosity() == QDebug::MinimumVerbosity)
+            continue;
+
+        #define QFONT_DEBUG_SKIP_DEFAULT(prop) \
+            if ((font.prop() == defaultFont.prop()) && stream.verbosity() == 1) \
+                continue;
+
+        QDebugStateSaver saver(debug);
+
+        switch (property) {
+        case QFont::FamilyResolved:
+            debug << font.family(); break;
+        case QFont::SizeResolved:
+            if (font.pointSizeF() >= 0)
+                debug << font.pointSizeF() << "pt";
+            else if (font.pixelSize() >= 0)
+                debug << font.pixelSize() << "px";
+            else
+                Q_UNREACHABLE();
+            break;
+        case QFont::StyleHintResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(styleHint);
+            debug.verbosity(1) << font.styleHint(); break;
+        case QFont::StyleStrategyResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(styleStrategy);
+            debug.verbosity(1) << font.styleStrategy(); break;
+        case QFont::WeightResolved:
+            debug.verbosity(1) << QFont::Weight(font.weight()); break;
+        case QFont::StyleResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(style);
+            debug.verbosity(0) << font.style(); break;
+        case QFont::UnderlineResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(underline);
+            debug << "underline=" << font.underline(); break;
+        case QFont::OverlineResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(overline);
+            debug << "overline=" << font.overline(); break;
+        case QFont::StrikeOutResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(strikeOut);
+            debug << "strikeOut=" << font.strikeOut(); break;
+        case QFont::FixedPitchResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(fixedPitch);
+            debug << "fixedPitch=" << font.fixedPitch(); break;
+        case QFont::StretchResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(stretch);
+            debug.verbosity(0) << QFont::Stretch(font.stretch()); break;
+        case QFont::KerningResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(kerning);
+            debug << "kerning=" << font.kerning(); break;
+        case QFont::CapitalizationResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(capitalization);
+            debug.verbosity(0) << font.capitalization(); break;
+        case QFont::LetterSpacingResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(letterSpacing);
+            debug << "letterSpacing=" << font.letterSpacing();
+            debug.verbosity(0) << " (" << font.letterSpacingType() << ")";
+            break;
+        case QFont::HintingPreferenceResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(hintingPreference);
+            debug.verbosity(0) << font.hintingPreference(); break;
+        case QFont::StyleNameResolved:
+            QFONT_DEBUG_SKIP_DEFAULT(styleName);
+            debug << "styleName=" << font.styleName(); break;
+        default:
+            continue;
+        };
+
+        #undef QFONT_DEBUG_SKIP_DEFAULT
+
+        debug << ", ";
+    }
+
+    if (stream.verbosity() > QDebug::MinimumVerbosity)
+        debug.verbosity(0) << "resolveMask=" << QFlags<QFont::ResolveProperties>(font.resolve_mask);
+    else
+        fontDescription.chop(2); // Last ', '
+
+    stream << fontDescription << ')';
+
+    return stream;
 }
 #endif
 
diff --git a/src/gui/text/qfont.h b/src/gui/text/qfont.h
index e86f06353a..35ef798275 100644
--- a/src/gui/text/qfont.h
+++ b/src/gui/text/qfont.h
@@ -147,6 +147,7 @@ public:
     Q_ENUM(SpacingType)
 
     enum ResolveProperties {
+        NoPropertiesResolved        = 0x0000,
         FamilyResolved              = 0x0001,
         SizeResolved                = 0x0002,
         StyleHintResolved           = 0x0004,
@@ -167,6 +168,7 @@ public:
         FamiliesResolved            = 0x20000,
         AllPropertiesResolved       = 0x3ffff
     };
+    Q_ENUM(ResolveProperties)
 
     QFont();
     QFont(const QString &family, int pointSize = -1, int weight = -1, bool italic = false);
@@ -335,6 +337,10 @@ private:
     friend Q_GUI_EXPORT QDataStream &operator>>(QDataStream &, QFont &);
 #endif
 
+#ifndef QT_NO_DEBUG_STREAM
+    friend Q_GUI_EXPORT QDebug operator<<(QDebug, const QFont &);
+#endif
+
     QExplicitlySharedDataPointer<QFontPrivate> d;
     uint resolve_mask;
 };